Modeling And Experiments Of Interactive Forces In AFM Nanomanipulation

New nano-structures, nano-materials and their specific properties have been discovered and studied with the development of nanotechnology. Due to good merits of the nano-materials, fabrication of high sensitive nano-devices and nano-electromechanical systems (NEMS) for applications in fields of biology, medicine, information has become hot research topics. As one of significant methods for nano-fabrication, AFM based three-dimensional nanomanipulation and nanoassembly has been widely used to fabricate three-dimensional nano-structures and functional nano-devices.Compared with the traditional macro-manipulation, adhesion forces in the nanoscale, instead of gravity, dominate interaction forces between manipulation tools and nano-objects due to the scale effect. Since adhesion forces is larger, it is hard to grasp the nano-object using a parallel nano-tweezer. In order to achieve nanoscale grasping and releasing operations, a dual-probe nano-tweezer based on the principle of atomic force microscopy is present. This nano-tweezer is formed by two AFM tips with a―V‖configuration. Compared with the parallel nano-tweezer, the presented non-parallel nano-tweezer can produce enough grasping force to overcome the adhesion forces between nano-objects and substrate, achieving three-dimensional manipulation of the nano-objects.Mechanisms of adhesion, contact and friction between nano-objects are studied, and interaction forces in AFM nanomanipulation is modeled. Effects from the environment humidity on the model and external load on the friction are analyzed. A experimental system of a dual-probe nano-tweezer is built. In different humidity, theoretical models are validated by measuring pull-off and friction forces between a microsphere probe and a silicon substrate.In this thesis, models of interaction forces in AFM nanomanipulation is built and validated by experiments performed on the developed dual-probe nano-tweezer. The research provide theoretical support for the realization of three-dimensional nanomainpulation of nano-structures and nano-devices.